The Supreme Court’s decision last summer in Bristol-Myers Squibb Co. v. Superior Court of California, 137 S. Ct. 1773 (2017), is my pick for “2017 Class Action Practitioners’ Case of the Year”––and it’s not even a class case.

One of the most exciting areas in the class action arena is personal jurisdiction. Stifle that yawn. The Supreme Court’s recent decisions in this area could have a major effect on the scope of class actions where the claims sound in state law. Plaintiffs’ lawyers have long sought to bring class actions in the most plaintiff-friendly venues. As a general proposition, a plaintiff would prefer to cram a big nationwide class of claims into the most favorable venue instead of having to bring either several single-state class actions in several venues or a nationwide class in a less-favorable venue. Where plaintiffs are successful, this kind of forum shopping makes class cases all the more difficult for defendants: Not only do defendants have to face the high stakes of a large number of aggregated claims in one action, they also have to fight all those claims in a hostile venue.

The Supreme Court’s recent decision in Bristol-Myers Squibb, has given defendants a powerful new argument against this tactic. Bristol-Myers Squibb involved a mass action in which nearly 600 plaintiffs who did not live in California joined their claims with California residents’ claims. The defendant challenged personal jurisdiction, but the California courts found specific jurisdiction to exist. By an 8-1 vote, the United States Supreme Court reversed, holding that the California courts could not exercise personal jurisdiction over the defendant as to claims of non-resident defendants who could not satisfy the well-settled test for specific jurisdiction. As a result, the plaintiffs face the choice of either bringing their nationwide class in a forum where the defendant is subject to general jurisdiction (i.e., state of incorporation of principal place of business, thanks to the Supreme Court’s recent Daimler decision) or limiting the class to those plaintiffs whose claims involve the kind of minimum contacts necessary to support the exercise of specific jurisdiction.

As mentioned above, Bristol-Myers Squibb is not a class action case––but that is likely of no consequence. The decision rests on the constitutional due process rights of defendants, and, under the Rules Enabling Act, the purely procedural class action rules cannot abrogate those rights. (We’ll address this point further in a future post, along with looking at how lower courts have applied Bristol-Myers Squibb in the class context.)

Practically speaking, Bristol-Myers Squibb should curb the most blatant forum shopping in diversity cases. Defendants should use it to channel more litigation to the jurisdictions where defendants are incorporated or headquartered or where the plaintiffs reside. The case may also lead to an increase in single-state class cases, which is a potential downside—but defendants can waive personal jurisdiction as a defense to permit consolidation where appropriate. The increase in state-specific suits may also make removal under diversity or CAFA easier, as plaintiffs will be less free to use joinder to defeat diversity jurisdiction and will likely run afoul of the no-similar-case rule of 28 U.S.C. § 1332(d)(4)(A)(ii). We also predict an uptick in multidistrict-litigation petitions, which both plaintiffs and defendants can perceive as an advantageous way of consolidating geographically dispersed litigation.